1. Field of the Invention
The invention relates to an electric adjusting device for a front seat of a motor vehicle, and more particularly to, an electric device for a front seat of a motor vehicle which causes a forward displacement of the front seat in response to folding the seat back forwards.
2. Description of the Related Art
DE 196 30 223 A1 discloses an adjusting device of the generic type in which the front seat can be adjusted by means of electric servomotors.
In the case of the adjusting devices which have been mentioned, an auxiliary device is provided for the forwards displacement of the front seat into an entry position and rearwards displacement into a rearwards-displacement position, as required. The entry and access to the rear seats in the case of two-door vehicles is intended to be facilitated by such an auxiliary device (easy-entry function, entry assistance). The known auxiliary device is concerned with front seats which are constructed from a seat lower part, which can be adjusted in the longitudinal direction by means of an electric motor, with a pivotable seat backrest. For this purpose, a release lever is provided on the seat back, which is used, in the release position, to release the seat back mechanically and enable it to fold forwards. When the seat backrest is pivoted forwards, an electric memory means retains the current position of use. The auxiliary device then moves the front seat forwards into the entry position enabling easy access to the rear seats. When the seat backrest is pivoted back, the front seat moves into a rearwards-displacement position which corresponds, for example, to the stored starting position.
In the event of the front seat having been set to a position situated comparatively far to the rear, there is the risk of a rear occupant becoming stuck when the front seat is displaced rearwards into the stored starting position. In order to prevent this, in German Patent Document DE 196 30 223 A 1, a blocking function is provided which restricts the rearwards displacement of the front seat to a maximum rearwards-displacement position.
However, in everyday use the rear seats are very frequently only used to store objects, for example a briefcase. In these cases, the restriction of the rearwards displacement is not required and for a large person sitting on the front seat is even undesirable, since the restriction has to be re-recorded each time by manual intervention.
Therefore, in German Patent Document DE 196 30 223 A 1, provision is made for a restriction of the rearwards displacement of the front seat, and the losses of comfort associated therewith for a large, front occupant, only to take place if the rear seat is actually also occupied b an occupant. This is determined by means in the rear seat arranged behind the front seat.
A disadvantage of this solution is the comparatively great outlay. It would furthermore be desirable if a user could control the extent of the forwards displacement and rearwards displacement of the front seat individually without therefore using the seat-adjustment operating unit which can normally only be operated comfortably from the front seats.
The object of the invention is to improve an electric adjusting device of the generic type for a front seat of a motor vehicle to the effect that the displacement of the front seat in the longitudinal direction for a user entering the vehicle can be controlled individually.
The present invention is aimed at one or more of the problems identified above.
According to the invention, the front seat is only displaced forwards by means of an electric motor if, after release of the seat back, the seat back has been folded forwards and at the same time the release lever is also actuated in the release position. If the desired position has been reached, the forwards displacement can be halted by returning the release lever into the neutral position. It is therefore possible only to move the seat as far forwards as is absolutely necessary, for example in order to place an attache case into the footwell in front of the rear seat.
If, in order to place an attache case onto the rear seat, only the seat back is to be folded over, a forwards displacement of the front seat can be suppressed by means of an appropriate manipulation. For this purpose, immediately after the release of the seat back the release lever has to be returned into the neutral position before the seat-back switch is actuated by the folding forwards of the seat back.
In one aspect of the present invention, the seat-back switch is arranged in such a manner that it is actuated as late as possible when the seat back has been folded forwards into the end position.
In another aspect of the present invention, a rearwards displacement of the front seat can be requested by pressing down the release lever beyond the neutral position, the rearwards displacement being possible, depending on the design in each case, irrespective of the angle of the seat back or only when the seat back is folded back into the position of use.
Further details and advantageous developments of the adjusting device according to the invention emerge from the other subclaims in conjunction with the following description.